Final answer:
Pink puffers often exhibit near-normal CO2 levels due to increased respiration efforts. Pneumonia can impair gas exchange, leading to elevated CO2 levels. The alveolar oxygen partial pressure is calculated using the respiratory quotient, reflecting the mixture of inspired and residual air in the lungs.
Step-by-step explanation:
In pink puffers, a subtype of patients with emphysema, CO2 levels in the blood can be near-normal or slightly elevated due to their increased effort to maintain gas exchange by breathing more deeply and rapidly, despite the loss of lung tissue and elasticity. The term pink puffer refers to the reddish complexion these patients often exhibit and their noticeable struggle to breathe or puff to expel air.
When the partial pressure of carbon dioxide is 45 mm Hg in the blood and 40 mm Hg in the alveoli, CO₂ will diffuse down its pressure gradient from the blood into the alveoli during respiration. Respiratory infections like pneumonia can disrupt this exchange by filling the alveoli with fluid or debris, impeding the diffusion of gases and potentially causing a rise in CO₂ levels in the bloodstream as the removal of carbon dioxide becomes less efficient.
The alveolar partial pressure of oxygen (PaO₂) can be calculated using the respiratory quotient (RQ) which indicates the ratio of CO₂ production to O₂ consumption. With an RQ of 0.8 and a PCO₂ in the alveoli of 40 mm Hg, the alveolar PO₂ is equal to the inspired PO₂ minus a value derived from the product of alveolar PCO₂ and the RQ.